Periodontal disease is a destructive inflammatory process which destroys the supporting structures of teeth. While this disease is relatively easy to identify in its advanced stages, early diagnosis of the disease has been a long-sought objective of research in this area, since such diagnosis would enable timely preventive measures to be taken. Periodontal disease is widespread, effecting a majority of people over 35 years of age, and is a major cause of tooth loss and destruction of supporting bone tissue.
Although the precise cause of inflammatory periodontal disease remains unclear, certain factors have been associated in the literature with its origin. These include local irritants, such as bacterial plaque, faulty restorations, and traumatic tooth contacts. Systematic factors, such as hormonal and nutritional status, also affect the course of the disease. Despite this variety of factors, it is widely accepted that the primary causative agent in periodontal disease is the bacterial plaque located in the gingival crevice (the space between the surface of the tooth and the gingiva). When plaque develops in this area, it constitutes one of the most dense concentrations of bacteria to which man is exposed. These and other factors are discussed in some detail in an article entitled "Diet and Oral Health", by Dominick P. DePaola, D.D.S., Ph.D. and Michael C. Alfano, D.M.D., Ph.D. appearing in "Nutrition Today", May/June 1977.
While considerable research has been conducted on individuals with periodontal disease, this research has heretofore failed to produce a reliable early diagnostic indicator for the existance of periodontal disease. For example, it has long been known that saliva from patients suffering from periodontal disease putrefies more rapidly than saliva from health oral cavities (Berg, M., Burrill, D.Y., and Fosdick, L.S. 1947, Chemical Studies In Periodontal Disease. IV. Putrefaction Rate As Index Of Periodontal Disease. J. Dent. Res. 26: 67-71; Law, D.B., Berg, M.S., and Fosdick, L.S. 1943. Chemical Studies In Periodontal Disease. J. Dent. Res. 22: 373-379). Of course, it has also been noted that other factors, such as monthly hormonal variations in female subjects, (as reported by Tonzetich, J., Preti, G., and Huggins, G.R. 1978, Changes In Concentrations Of Volatile Sulfur Compounds Of Mouth Air During The Menstrual Cycle. J. Int. Med. Res., 6: 245-254) may exert strong influences on saliva and mouth air samples, as may drug and medication use, dietary intake and normal dental hygienic procedures.
It is well documented that quantitative changes in the concentration of certain metabolites excreted in human body fluids, as well as in expired mouth air, can provide indications of a number of pathologic or physiologic events. For example, with respect to body fluids, see Jellum, et al, J. Anal. Chem. 45(7):1099-1106, 1973; Thompson and Markey, J. Anal. Chem. 47(8):1313-1321, 1976; Hutterer, Clin. Chem. 17(8):789-794, et al, 1971; Zlatkis, 789-794, et al, Chromatographia 6(2):67-70, 1973; Preti and Huggins, The Human Vagina, Chapter 10, (1978). For example, expired mouth air contains a complex mixture of organic compounds of both systemic and oral origin (Tonzetich, Arch Oral Biology, Volume 16, pages 587-597 1971; Dubowski, Clin. Chem. 20(8):966-972, 1974; Teranishi, et al, Anal. Chem. 44(1):18-20, 1972). Protocols have been devised for determining blood ethanol levels via its concentration in breath (Dubowski, Ibid., 1974). In addition to ethanol, other organic metabolites of systemic origin found in breath have been identified (Chen, et al, J. of Lab. and Clinical Medicine, Vol. 75, No. 4, pp. 622-627 and pp. 628-635, 1970 a, b; Dubowski, Ibid., 1974).
Saliva consists of secretions from the parotid, submandibular and sublingual glands and fluids from numerous minor glands distributed throughout the oral cavity. In addition, mixed saliva contains gingival exudate, leukocytes, exfoliated epithelial cells, microorganisms and food debris (Orban, Oral Histology and Embryology, pp. 269-271, 1972; MacFarlane and Mason, Oral Mucosa In Health, Blackwell Scientific Publications, pp. 113-116, 1975).
The nature and abundance of many of the inorganic and organic constituents found in saliva have been documented (Afonsky, University of Alabama Press, pp 97-104 1961; MacFarlane and Mason, Ibid., 1975). Although many of the investigations of the organic constituents of saliva have been aimed primarily at characterizing the nature of the large molecules present, some smaller (M.W..ltoreq.450) organic molecules have been identified. These are listed in Table 1. Lipids present in skin sebum may also be present in saliva (Miles, British Dental Journal 104:235-248, 1958; MacFarlane and Mason, Ibid., 1975). The putrefactive action of microorganisms on proteinaceous substrates in saliva is the source of many volatiles found in mouth air (see below) (Spouge, The Dental Practitioner and Dental Record, Vol. XIV(8):307-317, 1964; Tonzetich and Kestenbaum, Arch.Oral Biol. 14:815-827, 1969; McNamara et al, Oral Surg. 34:41-48, 1972). The distribution of normal microflora in the various areas of the oral cavity has recently been reviewed (Hardie and Bowden, The Normal Microbial Flora of Man, pp. 47-61, 1974), and many of the microorganisms and indigenous to the saliva, tongue, dental plaque and gingival crevice are reported to produce volatiles (Berg and Fosdick, J. Dental Res., Vol. 26, pp. 67-71; J. Dental Res., Vol. 25, pp. 73-81, 1946; McNamara et al, Ibid., 1972).
A number of volatile compounds produced are primarily in the oral cavity. The volatile sulfur compounds, hydrogen sulfide (H.sub.2 S), methylmercaptan (CH.sub.3 SH) and dimethylsulfide (CH.sub.3).sub.2 S, produced by metabolic processes within the oral cavity, have been extensively studied because they are responsible for oral malodor (Tonzetich and Kestenbaum, Ibid., 1969; Tonzetich, Arch. Oral Biol. 4:587-597, 1971). This malodor is manifested due to the production of volatile compounds through putrefaction by microorganisms (Berg and Fosdick, Ibid., 1946) on proteinaceous substrates, exfoliated epithelial cells, salivary corpuscles, food debris, saliva and blood. The proteins are degraded via proteolysis to peptides and amino acids which are further metabolized to the volatile sulfur compounds (VSC) (Tonzetich and Kestenbaum, Ibid., 1969). The VSC in mouth air are decreased by brushing and rinsing. All individuals produce them, but they are accentuated in tissue degenerative conditions such as gingivitis, periodontitis, and acute necrotizing ulcerative gingivitis (J. Periodont. 48:13-20, 1977).
In addition, general relationships between oral conditions favorable for VSC production and phases of the menstrual cycle have been demonstrated by several studies. Elevated levels of estrogens and progesterone appear to lower the threshold sensitivity of human periodontal tissues to inflammation (Loe, J. of Periodentology, V. 36(1):37/209-45/217, 1965; Loe and Sillness, Acta Odont. Scand. 21:533-549, 1963). The severity of tissue involvement is correlated with an increase in the volume of gingival fluid and is greatest near ovulation and least at menstruation (Lindhe and Attstrom, J. Periodont. Res. 2:194-198, 1967; Lindge et al, J. Periodont. Res. 3:12-20, 1968). The greatest fluctuations in the volume of gingival exudate due to hormonal influences occur in females with pre-existing chronic gingivitis (Holm-Pedersen and Loe, J. Perio. Res. 2:13-20, 1967). Other factors that lead to VSC production are increases in the number of desquamated epithelial cells during menstruation, during ovulation ((Iusem, Oral Med. 3:1516-1520, 1950; Main and Richie, Brit. J. Dermatology 79:20-30, 1967), in periodontitis (Dreizen et al, Oral Surgery, Oral Medicine and Oral Pathology 69:278-283, 1965), and during menstruation and ovulation due to elevated total bacterial counts.
A recent study at the Monell Chemical Senses Center employing high sensitivity GC has provided the first direct evidence that VSC may fluctuate during the menstrual cycle and correlate with changes in circulating sex steroid hormone levels (Tonzetich et al, J. Internat. Med. Res. 6:245-254, 1978). Consequently, in examining ovulating female patients for volatile mouth air constituents, the time of the menstrual cycle should be noted.
Saliva samples from patients with periodontal disease putrefy more rapidly than do those without this problem (Berg et al, J. Dental Res., Vol. 26, pp. 67-71, 1947; Law et al, J. Dental Res. 22:373-379, 1943). This may be due to the increase in number and type of microorganisms. Regardless of the cause of the change, the salivary putrefaction rate as measured by the rate of volatile production may be an indication of a patient's oral health.
One of the volatile sulfur compounds, H.sub.2 S, is highly toxic to the epithelial tissues of the throat and eyes (Grant, WHM, "Toxicology of the Eye", Charles Thomas, Publisher, 1962). This compound, which is increased in inflamed periodontal pockets, can be detected via its interaction with metal ions, such as barium or mercury (Rizzo, Periodentics 5:233-236, 1967) as well as by the highly sensitive procedures of gas chromatography and mass spectrometry (Tonzetich and Richter, Arch. Oral Biol. 9:39-45, 1964). Furthermore, hydrogen sulfide, as well as the thiols penicillamine and cysteamine, have been shown to solubilize collagen in vitro (Tonzetich and Lo, Arch. Oral Biol. 23:875-880, 1976). Thus it is conceivable that this common product of bacterial metabolism may contribute to the etiology of periodontal disease. Certain low molecular weight nitrogen-containing compounds, such as ammonia and urea (Golub et al, J. Periodontal Res. 6:243-251, 1971), which are found in gingival crevicular fluid, have also been implicated as possible etiologic factors in periodontal diseases.
In view of the above, it may be seen that the causes and influences and aggravating factors effecting periodontal disease are complex, thereby heightening the desirability of developing early detection and treatment methods.